阅读说明：本技术 一种石灰-电石联合生产系统和方法 (Lime-calcium carbide combined production system and method ) 是由 贾鹏 于 2021-02-03 设计创作，主要内容包括：本发明涉及一种石灰-电石联合生产系统和方法,装置包括气化加热炉、石灰回转窑、电石回转窑和CO-2回收装置。气化加热炉为回转窑结构,包括燃料喷嘴、循环气体出口、灰渣出口和引射器。气化加热炉的循环气体出口一路连接到石灰回转窑,一路连接到电石回转窑。生产过程包括石灰回转窑的石灰尾气预热石灰石原料后一路到CO-2回收装置回收纯净CO-2,另一路到循环泵入口。电石回转窑的电石尾气经引射器进入气化加热炉作气体然料。本发明通过气化加热炉、电石回转窑和石灰回转窑相结合生产电石和石灰,气化加热炉煤气化得到的高温热载气向电石回转窑和石灰回转窑供热,提高了燃煤热能利用率,减少了燃煤消耗量。(The invention relates to a lime-calcium carbide combined production system and method, and the device comprises a gasification heating furnace, a lime rotary kiln, a calcium carbide rotary kiln and CO 2 And (5) a recovery device. The gasification heating furnace is of a rotary kiln structure and comprises a fuel nozzle, a circulating gas outlet, an ash outlet and an ejector. One path of a circulating gas outlet of the gasification heating furnace is connected to the lime rotary kiln, and the other path of the circulating gas outlet is connected to the calcium carbide rotary kiln. The production process comprises that lime tail gas of the lime rotary kiln preheats the raw material of the limestone and then leads the limestone to CO 2 The recovery device recovers pure CO 2 And the other path is connected to the inlet of the circulating pump. The tail gas of the calcium carbide rotary kiln enters a gasification heating furnace through an ejector to be used as a gas fuel. The invention produces calcium carbide and lime by combining a gasification heating furnace, a calcium carbide rotary kiln and a lime rotary kiln, and high-temperature hot carrier gas obtained by coal gasification of the gasification heating furnaceHeat is supplied to the calcium carbide rotary kiln and the lime rotary kiln, the utilization rate of heat energy of fire coal is improved, and the consumption of the fire coal is reduced.)

1. A lime-calcium carbide combined production system comprises a lime rotary kiln (2), a calcium carbide rotary kiln (17), a limestone storage bin (26), a calcium carbide raw material bin (19) and CO₂A recovery device (16); the lime rotary kiln (2) is provided with a circulating gas inlet (9), a lime tail gas outlet (3), a limestone raw material inlet (29) and a lime product outlet (10), the limestone silo (26) is connected to the limestone raw material inlet (29), and the limestone silo (26) is provided with a flue gas inlet (36) and a flue gas outlet (37); the calcium carbide rotary kiln (17) is provided with a circulating gas inlet (9), a calcium carbide tail gas outlet (32), a calcium carbide raw material inlet (8) and a calcium carbide product outlet (18), and the calcium carbide raw material bin (19) is connected to the calcium carbide raw material inlet (18)8) (ii) a The method is characterized in that: the system is provided with a gasification heating furnace (1), the gasification heating furnace is of a rotary kiln structure and comprises a fuel nozzle (6), a circulating gas outlet (4), an ash outlet (20) and an ejector (22); the ejector (22) is provided with an ejection gas inlet (21), a tail gas ejection inlet (5) and an ejection opening, and the ejection opening is connected to the gasification heating furnace (1); the calcium carbide product outlet (18) is connected to the transport vehicle (7) through a calcium carbide waste heat recoverer (12), the lime product outlet (10) is connected to a lime bin (28) through a lime waste heat recoverer (27), the lime bin (28) is provided with a lime cooling gas inlet (35), and the ash slag outlet (20) is connected to an ash slag pool (25) through an ash slag waste heat recoverer (24); the transport vehicle (7) is provided with a transport vehicle protection gas inlet (34), and the ash pond (25) is provided with an ash pond protection gas inlet (33); a calcium carbide tail gas outlet (32) of the calcium carbide rotary kiln (17) is connected to a tail gas injection inlet (5), a lime tail gas outlet (3) is connected to a flue gas inlet (36), a flue gas outlet (37) is divided into two paths, and one path is connected to CO₂A recovery device (16), one path of which is connected to the inlet of the circulating pump (23); the outlet of the circulating pump (23) is divided into five paths, the first path is connected to the air seal chamber (30), the second path is connected to the injection gas inlet (21), the third path is connected to the ash pool protective gas inlet (33), the fourth path is connected to the transport vehicle protective gas inlet (34), and the fifth path is connected to the lime cooling gas inlet (35); the circulating gas outlet (4) of the gasification heating furnace (1) is divided into two paths, one path is connected to the circulating gas inlet (9) of the calcium carbide rotary kiln (17) through a high-temperature hot carrier gas circulating pipeline (11), and the other path is connected to the circulating gas inlet (9) of the lime rotary kiln (2) through a high-temperature hot carrier gas conveying pipeline (15).

2. The lime-calcium carbide combined production system as set forth in claim 1, wherein: the calcium carbide rotary kiln is provided with a kiln head cover (31), an air seal chamber (30) is arranged between the kiln head cover and a kiln body, the kiln head cover is provided with a circulating gas inlet (9) and a calcium carbide product outlet (18), the circulating gas inlet (9) is positioned in the middle of the air seal chamber (30), and the calcium carbide product outlet (18) is positioned at the lower part of the air seal chamber (30); the seal includes but is not limited to knife-edge dynamic seal, and multiple labyrinth seals including but not limited to labyrinth seals can be adopted.

3. The lime-calcium carbide combined production system as set forth in claim 1, wherein: the fuel nozzle (6) is of a coaxial sleeve structure, the center of the fuel nozzle is a coal powder channel (14), and the periphery of the coal powder channel is an oxygen channel (13); the gas seal chamber (30) can be one or more of a plurality of seals, a static seal or a dynamic seal, a labyrinth combination of a mechanical seal and a gas seal, and can be sealed by a gas curtain using carbon dioxide, nitrogen, inert gas or a mixture thereof, so that the gas in the rotary kiln does not enter the atmosphere and the atmosphere does not enter the rotary kiln.

4. The lime-calcium carbide combined production system as set forth in claim 1, wherein: the lime rotary kiln is replaced by a lime shaft kiln or a dividing wall rotary kiln, and the lime shaft kiln is a beam kiln, a sleeve kiln, a double-chamber kiln or an annular opposite burning kiln.

5. A production method of the lime-calcium carbide combined production system as set forth in claim 1, which is characterized in that: the lime raw material in the limestone bin (26) is preheated by lime tail gas discharged from the lime rotary kiln (2) and then enters the lime rotary kiln (2) from a limestone raw material inlet (29), and coke and lime in the calcium carbide raw material bin (19) enter the calcium carbide rotary kiln (17) from a calcium carbide raw material inlet (8); the dried coal powder and pure oxygen are sprayed into the gasification heating furnace (1) through a fuel nozzle (6), and the coal powder, the pure oxygen and the calcium carbide tail gas are completely combusted in the gasification heating furnace to generate CO basically₂Also allows for a certain proportion of CO, while also allowing for a certain amount of H including, but not limited to₂O、CH₄And H₂High-temperature gas is discharged from a circulating gas outlet (4), and one path of high-temperature gas enters the calcium carbide through a high-temperature hot carrier gas circulating pipeline (11) and a circulating gas inlet (9)The rotary kiln (17) heats the calcium carbide raw material to produce calcium carbide, and the other path of the calcium carbide raw material enters the lime rotary kiln (2) through the high-temperature hot carrier gas conveying pipeline (15) and the circulating gas inlet (9) to heat and calcine limestone by using sensible heat to produce lime; the lime tail gas calcined in the lime rotary kiln is divided into two paths after preheating the limestone raw material, wherein one path is connected to CO₂The recovery device (16) purifies and recovers pure CO₂Removing water, purifying, and making into food grade or industrial grade CO₂The other path of the product is connected to the inlet of a circulating pump (23); CO at the outlet of the circulation pump (23)₂Divided into five parts, the first part being sealed with a gas seal chamber (30), CO in the gas seal chamber (30)₂The air can be prevented from entering the rotary kiln, meanwhile, the gas in the rotary kiln is prevented from leaking, the second part is used as the working gas of the ejector from the guide gas inlet (21), the third part is used as the protective atmosphere for the ash pool (25) from the ash pool protective gas inlet (33) to prevent the atmosphere from entering the gasification heating furnace, the fourth part is used as the protective atmosphere for the transport vehicle (7) from the transport vehicle protective gas inlet (34) to prevent the atmosphere from entering the calcium carbide rotary kiln, and the fifth part is used as the cooling gas of the finished product lime from the lime cooling gas inlet (35); calcium carbide tail gas of the calcium carbide rotary kiln (17) enters the gasification heating furnace (1) through a calcium carbide tail gas outlet (32) and a tail gas ejection inlet (5) of the ejector (22) to be used as gas fuel.

6. The lime-calcium carbide joint production method as set forth in claim 5, wherein: the coal powder and the coke can be replaced by other carbonaceous materials, and the method of gas circulation while gasifying can obviously reduce the consumption of the carbonaceous materials.

7. The lime-calcium carbide joint production method as set forth in claim 5, wherein: high-temperature ash discharged from an ash outlet (20) of the gasification heating furnace (1) is recycled through an ash waste heat recoverer (24) and then enters an ash pool (25) for recycling; lime produced by the lime rotary kiln (2) enters a lime bin (28) after heat is recovered by a lime waste heat recoverer (27); the liquid calcium carbide produced by the calcium carbide rotary kiln (17) enters a calcium carbide waste heat recoverer (12) through a calcium carbide product outlet (18) to recover waste heat and then falls into a transport vehicle (7); and the ash slag pool (25) and the transport vehicle (7) both adopt carbon dioxide protective atmosphere.

8. The lime-calcium carbide joint production method as set forth in claim 5, wherein: the high-temperature gas temperature of the circulating gas outlet (4) of the gasification heating furnace (1) is 800-3000 ℃; the calcium carbide tail gas temperature at the calcium carbide tail gas outlet (32) is 100-2000 ℃.

9. The lime-calcium carbide combined production system as set forth in claim 5, wherein: the calcium carbide rotary kiln (17) can be applied to any reduction smelting, high-temperature calcination, boiler steam power generation and other processes; the calcium carbide rotary kiln (17) can be replaced by various vertical heating kilns, including but not limited to reduction smelting, or high-temperature calcining, or power generation; the coal dust and coke can be replaced by other carbonaceous materials, and the coal dust carrier can be carbon dioxide, water vapor, water, nitrogen, helium, argon, other inert gases or mixtures thereof; the ejector (22) can be replaced by other power devices which can achieve the purpose of ejection; the ejector (22) and the fuel nozzle (6) are close to each other as much as possible, so that the pulverized coal, the oxygen and the combustible gas are fully mixed and contacted, and the reaction efficiency of the combustible gas is increased; the raw materials and the raw materials recovered from the tail gas are conveyed by carrier gas and sprayed into the rotary kiln or various vertical heating furnaces through a calcium carbide raw material inlet (8), and any method and device for enabling the tail gas to carry little raw material powder out of the rotary kiln or various vertical heating furnaces can be adopted in the process so as to reduce the raw material powder carried by the tail gas; the method comprises the steps of conveying the raw materials by carbon dioxide and other stable gases, laterally spraying the raw materials to the inner wall of a high-temperature molten material of a rotary kiln or various vertical heating furnaces through a calcium carbide raw material inlet (8), bonding the raw material powder on the high-temperature molten material, and reducing the raw material powder carried by tail gas.

10. The lime-calcium carbide combined production system as set forth in claim 5, wherein: according to the process conditions, the CO can be remained and removed at the circulating gas outlet of the gasification heating furnace₂And H₂If the combustible gas is the combustible gas except the O, the gas which is sent to the lime kiln from the high-temperature hot carrier gas conveying pipeline needs to be subjected to afterburning by adding oxygen in the lime kiln, and the gas can be subjected to afterburning or not when being sent to a circulating gas inlet (9) of the calcium carbide rotary kiln (17), and directly enters the calcium carbide rotary kiln (17).

11. The lime-calcium carbide combined production system as set forth in claim 5, wherein: the calcium carbide rotary kiln (17), the lime rotary kiln (2) and the gasification heating furnace (1) are allowed to have a structure only containing refractory materials, and kiln skins different from the refractory materials are hung on the refractory materials outside the inner ring; the calcium carbide rotary kiln and the gasification heating furnace system can also be used for other reduction smelting.

12. The lime-calcium carbide combined production system as set forth in claim 5, wherein: the discharge ports of all product materials and slag of the rotary kiln are sealed by carbon dioxide, so that the rotary kiln and the atmosphere are prevented from communicating; the calcium carbide pot adopts a double-layer carbon dioxide protection device to prevent the calcium carbide pot from being mixed with the atmosphere in the calcium carbide rotary kiln; any position of the calcium carbide rotary kiln and the gasification heating furnace allows an auxiliary heating device for plasma heating to be arranged; the calcium carbide raw material can also be made into shapes including but not limited to balls and the like and enters the calcium carbide rotary kiln; an ash outlet of the gasification heating furnace is also allowed to be arranged on the outlet side of the circulating gas; the gasification heating furnace (1) has higher pressure grade than the lime rotary kiln (2) and the calcium carbide rotary kiln (17); the gasification heating furnace, the calcium carbide rotary kiln, the lime rotary kiln and the kiln head cover are all composed of refractory materials, heat-insulating materials and steel shells; all equipment and pipelines with temperature are provided with refractory material structures or water-cooled wall structures with internal heat preservation or external heat preservation or internal and external heat preservation;

when the calcium carbide rotary kiln is not in production and the ejector does not operate, high-temperature hot carrier gas discharged from a circulating gas outlet of the gasification heating furnace automatically enters the lime rotary kiln.

Technical Field

The invention belongs to the field of energy and mineral processing, and relates to a lime-calcium carbide combined production system and method.

Background

The calcium carbide production has high energy consumption, and the traditional calcium carbide production method is an electric heating method, namely, the calcium carbide product is obtained from calcium carbide raw materials by an electric heating method. The energy consumption cost of calcium carbide production accounts for a large proportion of the total production cost, and belongs to the high energy consumption industry. Because electricity is a secondary energy source (the heat energy utilization rate of thermal power generation is about 30% -40%), the production cost of calcium carbide is high when calcium carbide is produced by an electric heating method, and the industrial calcium carbide is lack of competitiveness in the market. The coal gasification calcium carbide production uses coal or coke incomplete combustion (high-temperature gasification) to provide heat, so that the limitation of the power generation efficiency is removed, and the theoretical possibility is provided for improving the utilization rate of primary energy.

The Carbon (CO) in the calcium carbide raw material can be consumed by a large amount of carbon dioxide generated by combustion in the calcium carbide production environment at high temperature₂+ C =2 CO). Because other oxidizing agents in the carbide reaction system may consume carbon or carbide which can be used as a reducing agent, the formation reaction of carbide must be carried out in a reducing atmosphere. The incomplete combustion of coal or coke can generate high-purity carbon monoxide gas and provide heat required by calcium carbide production. Thermochemical analysis revealed that the standard enthalpy of formation of CO is insufficient for CO₂30% of the total, and the same amount of heat, incomplete combustion usually consumes more carbonaceous feedstock (coke or coal).

Setting the outlet temperature of calcium carbide tail gas at 1500 ℃, using CO₂When the mixture of pure oxygen and coal is used as a high-temperature gasifying agent of coal, the consumption of fuel coal is 5.8 times that of the coal used as a calcium carbide raw material. Under the above working conditions, most of coal consumed by the coal gasification calcium carbide production is used as fuel, and the proportion of the fuel actually used for the calcium carbide production is very low. The reason is that the gasified coal gas passes through the calcium carbide unit, CO in the high-temperature tail gas exists, and leaves the calcium carbide production system, and the energy of the coal is mainly discharged out of the calcium carbide production system in the forms of the sensible heat and the combustion heat of the calcium carbide tail gas. In order to ensure that the yield of the calcium carbide is increased only by increasing the gasification amount of the coal, the coal consumption is necessarily high. Therefore, how to improve the fuel utilization rate of the coal gasification calcium carbide production and reduce the fuel consumption becomes a technical problem to be solved urgently.

Disclosure of Invention

The invention aims to provide a lime-calcium carbide combined production system, which obtains high-temperature CO through a gasification heating furnace₂The method directly supplies heat to calcium carbide production equipment and a lime rotary kiln, and utilizes tail gas circulation to control the coal gasification temperature, thereby improving the utilization rate of heat energy of the coal and reducing the consumption of the coal. The invention also aims to provide a lime-calcium carbide combined production method.

The technical scheme of the invention is as follows:

a lime-calcium carbide combined production system comprises a lime rotary kiln and a calcium carbide rotary kilnKiln, limestone bin, calcium carbide raw material bin and CO₂And (5) a recovery device. The lime rotary kiln is provided with a circulating gas inlet, a lime tail gas outlet, a limestone raw material inlet and a lime product outlet, a limestone bin is connected to the limestone raw material inlet, and the limestone bin is provided with a flue gas inlet and a flue gas outlet. The calcium carbide rotary kiln is provided with a circulating gas inlet, a calcium carbide tail gas outlet, a calcium carbide raw material inlet and a calcium carbide product outlet, and a calcium carbide raw material bin is connected to the calcium carbide raw material inlet. The system is provided with a gasification heating furnace which is of a rotary kiln structure and comprises a fuel nozzle, a circulating gas outlet, an ash outlet and an ejector. The ejector is provided with an ejection gas inlet, a tail gas ejection inlet and an ejection opening, and the ejection opening is connected to the gasification heating furnace. The calcium carbide product outlet is connected to the transport vehicle through a calcium carbide waste heat recoverer, the lime product outlet is connected to a lime bin through a lime waste heat recoverer, the lime bin is provided with a lime cooling gas inlet, and the ash residue outlet is connected to an ash residue pool through an ash residue waste heat recoverer. The transport vehicle is provided with a transport vehicle protection gas inlet, and the ash residue pool is provided with an ash residue pool protection gas inlet. The calcium carbide tail gas outlet of the calcium carbide rotary kiln is connected to the tail gas injection inlet, the lime tail gas outlet is connected to the flue gas inlet, the flue gas outlet is divided into two paths, one path is connected to CO₂And one path of the recovery device is connected to the inlet of the circulating pump. The outlet of the circulating pump is divided into five paths, the first path is connected to the air seal chamber, the second path is connected to the injection gas inlet, the third path is connected to the ash pool protective gas inlet, the fourth path is connected to the transport vehicle protective gas inlet, and the fifth path is connected to the lime cooling gas inlet. And a circulating gas outlet of the gasification heating furnace is divided into two paths, one path is connected to a circulating gas inlet of the calcium carbide rotary kiln through a high-temperature hot carrier gas circulating pipeline, and the other path is connected to a circulating gas inlet of the lime rotary kiln through a high-temperature hot carrier gas conveying pipeline.

Specifically, the calcium carbide rotary kiln is provided with a kiln head cover, an air seal chamber is arranged between the kiln head cover and a kiln body, the kiln head cover is provided with a circulating gas inlet and a calcium carbide product outlet, the circulating gas inlet is located in the middle of the air seal chamber, and the calcium carbide product outlet is located in the lower portion of the air seal chamber. The seal includes but is not limited to knife-edge dynamic seal, and multiple labyrinth seals including but not limited to labyrinth seals may be used.

Specifically, the fuel nozzle is of a coaxial sleeve structure, the center of the fuel nozzle is a coal powder channel, and an oxygen channel is arranged around the coal powder channel. The gas seal chamber can be one or more than one seal, can be a static seal or a dynamic seal, can be a combination of a mechanical seal and a gas seal of a labyrinth, and can be sealed by using a gas curtain including but not limited to carbon dioxide, nitrogen, inert gas or a mixture of the carbon dioxide, the nitrogen, the inert gas or the mixture of the carbon dioxide, the nitrogen and the inert gas to ensure that the gas in the rotary kiln does not enter the atmosphere and the atmosphere does not enter the rotary kiln.

Specifically, the lime rotary kiln is replaced by a lime shaft kiln or a dividing wall rotary kiln, and the lime shaft kiln is a beam kiln, a sleeve kiln, a double-chamber kiln or an annular opposite burning kiln.

Specifically, the limestone raw materials in the limestone silo are preheated by lime tail gas discharged from the lime rotary kiln and then enter the lime rotary kiln through a limestone raw material inlet, and coke and lime in the calcium carbide raw material silo enter the calcium carbide rotary kiln through a calcium carbide raw material inlet. The dried coal powder and pure oxygen are sprayed into the gasification heating furnace through a fuel nozzle, and the coal powder, the pure oxygen and the calcium carbide tail gas are completely combusted in the gasification heating furnace to generate CO basically₂Also allows for a certain proportion of CO, while also allowing for a certain amount of H including, but not limited to₂O、CH₄And H₂High-temperature gas is discharged from a circulating gas outlet, one path of the high-temperature gas enters the calcium carbide rotary kiln through the high-temperature hot carrier gas circulating pipeline and the circulating gas inlet to heat calcium carbide raw materials to produce calcium carbide, and the other path of the high-temperature gas enters the lime rotary kiln through the high-temperature hot carrier gas conveying pipeline and the circulating gas inlet to heat and calcine limestone by using sensible heat to produce lime. The lime tail gas calcined in the lime rotary kiln is divided into two paths after preheating the limestone raw material, wherein one path is connected to CO₂The recovery device purifies and recovers pure CO₂Removing water, purifying, and making into food grade or industrial grade CO₂The other path of the product is to the inlet of the circulating pump. CO at outlet of circulating pump₂The first part is sealed with a gas seal chamber containing CO₂Can prevent air from entering the rotary kiln and simultaneously prevent the gas in the rotary kiln from leaking, the second part is used as the working gas of the ejector from the guiding gas inlet, and the third part is used for providing protective atmosphere for the ash slag pool from the ash slag pool protective gas inletAnd the fourth part provides protective atmosphere for the transport vehicle from the transport vehicle protective gas inlet, so that the atmosphere is prevented from entering the calcium carbide rotary kiln, and the fifth part is used as cooling gas of finished lime from the lime cooling gas inlet. Calcium carbide tail gas of the calcium carbide rotary kiln enters the gasification heating furnace through a calcium carbide tail gas outlet and a tail gas ejection inlet of the ejector to be used as gas fuel.

Specifically, the coal dust and the coke can be replaced by other carbonaceous materials, and the method of performing gas circulation while gasifying can obviously reduce the consumption of the carbonaceous materials.

Specifically, high-temperature ash discharged from an ash outlet of the gasification heating furnace is recycled through an ash waste heat recoverer and then enters an ash pool for recycling. Lime produced by the lime rotary kiln enters a lime bin after heat is recovered by a lime waste heat recoverer. Liquid calcium carbide produced by the calcium carbide rotary kiln enters a calcium carbide waste heat recoverer through a calcium carbide product outlet to recover waste heat and then falls into a transport vehicle. The ash pond and the transport vehicle both adopt carbon dioxide protective atmosphere.

Specifically, the temperature of the high-temperature gas at the circulating gas outlet of the gasification heating furnace is 800-3000 ℃. The temperature of the calcium carbide tail gas at the calcium carbide tail gas outlet is 100-2000 ℃.

Specifically, the calcium carbide rotary kiln can be applied to any reduction smelting, high-temperature calcination, boiler steam power generation and other processes. The calcium carbide rotary kiln can be replaced by various vertical heating kilns, including but not limited to reduction smelting, or high-temperature calcining, or power generation. The coal fines and coke may be replaced by other carbonaceous materials and the coal fines carrier may be any material including, but not limited to, carbon dioxide, steam, water, nitrogen, helium, argon, other inert gases, or mixtures thereof. The ejector can be replaced by other power devices which can achieve the purpose of ejection. The ejector and the fuel nozzle are close to each other as much as possible, so that the pulverized coal, the oxygen and the combustible gas are mixed and contacted sufficiently, and the reaction efficiency of the combustible gas is increased. The raw material and the raw material recovered from the tail gas are conveyed by the carrier gas and sprayed into the rotary kiln or various vertical heating furnaces through the calcium carbide raw material inlet, and any method and device which enable the tail gas to carry little raw material powder out of the rotary kiln or various vertical heating furnaces can be adopted in the process, so that the raw material powder carried by the tail gas is reduced. The method comprises the steps of conveying the raw materials by carbon dioxide and other stable gases, and laterally spraying the raw materials to the inner wall of the high-temperature molten material of the rotary kiln or various vertical heating furnaces through a calcium carbide raw material inlet to enable the raw material powder to be bonded on the high-temperature molten material, so as to reduce the raw material powder carried by tail gas.

In particular, depending on the process conditions, the CO removal can also be retained at the recycle gas outlet of the gasification furnace₂And H₂And if so, adding oxygen into the lime kiln to perform afterburning on the gas from the high-temperature hot carrier gas conveying pipeline to the lime kiln, wherein the gas can be afterburned or not after being burnt and directly enters the calcium carbide rotary kiln when reaching a circulating gas inlet of the calcium carbide rotary kiln.

Specifically, the calcium carbide rotary kiln, the lime rotary kiln and the gasification heating furnace are allowed to have a structure only containing refractory materials, and kiln skins different from the refractory materials are hung on the refractory materials outside the inner ring. The calcium carbide rotary kiln and the gasification heating furnace system can also be used for other reduction smelting.

Specifically, all product material discharge ports and slag discharge ports of the rotary kiln are sealed by carbon dioxide, so that the rotary kiln and the atmosphere are prevented from communicating. The carbide pot adopts a double-layer carbon dioxide protection device to prevent the carbide pot from being mixed with the atmosphere in the carbide rotary kiln. Any position of the calcium carbide rotary kiln and the gasification heating furnace allows an auxiliary heating device for plasma heating to be arranged. The calcium carbide raw material can also be made into shapes including but not limited to balls and the like and enters the calcium carbide rotary kiln. The ash outlet of the gasification furnace is also allowed to be provided on the circulating gas outlet side. The gasification heating furnace has a higher pressure rating than the lime rotary kiln and the carbide rotary kiln. The gasification heating furnace, the calcium carbide rotary kiln, the lime rotary kiln and the kiln head cover are all composed of refractory materials, heat-insulating materials and steel shells. All equipment and pipelines with temperature are provided with refractory material structures or water-cooled wall structures with internal heat preservation or external heat preservation or internal and external heat preservation. When the calcium carbide rotary kiln is not in production and the ejector does not operate, high-temperature hot carrier gas discharged from a circulating gas outlet of the gasification heating furnace automatically enters the lime rotary kiln.

According to the lime-calcium carbide combined production system, calcium carbide and lime are produced by combining the gasification heating furnace, the calcium carbide rotary kiln and the lime rotary kiln, high-temperature hot carrier gas obtained by coal gasification of the gasification heating furnace directly supplies heat to the calcium carbide rotary kiln and the lime rotary kiln, and the temperature of coal gasification is controlled by tail gas circulation, so that the utilization rate of heat energy of coal is improved, and the consumption of the coal is reduced. According to the invention, the concentration of carbon monoxide in the coal gas at the outlet of the gasification heating furnace is adjusted by adjusting the oxygen/carbon ratio, and the theoretical combustion temperature of carbon in pure oxygen can be reduced after the low-temperature calcium carbide tail gas is circulated to the gasification heating furnace until the temperature of the coal gas at the outlet of the gasification heating furnace reaches the specified value of 2200-2300 ℃. The method for injecting the calcium carbide tail gas by using the ejector and performing gas circulation while gasifying can obviously reduce the consumption of carbon-containing substances, can reduce the use amount of oxygen by using carbon dioxide and water vapor in the tail gas, realizes zero emission of carbon dioxide, reduces the cost, realizes an environment-friendly production method, and also produces carbon dioxide as a byproduct.

Drawings

FIG. 1 is a schematic view of a lime-calcium carbide combined production system according to the present invention;

FIG. 2 is a schematic view of the rotary kiln discharge and sealing of the present invention;

FIG. 3 is a schematic structural view of a fuel nozzle of the present invention.

Wherein: 1-gasification heating furnace, 2-lime rotary kiln, 3-lime tail gas outlet, 4-circulating gas outlet, 5-tail gas injection inlet, 6-fuel nozzle, 7-transport vehicle, 8-calcium carbide raw material inlet, 9-circulating gas inlet, 10-lime product outlet, 11-high-temperature hot carrier gas circulating pipeline, 12-calcium carbide waste heat recoverer, 13-oxygen channel, 14-coal powder channel, 15-high-temperature hot carrier gas conveying pipeline, 16-CO₂The recycling device comprises 17-calcium carbide rotary kiln, 18-calcium carbide product outlet, 19-calcium carbide raw material bin, 20-ash residue outlet, 21-injection gas inlet, 22-injector, 23-circulating pump, 24-ash residue waste heat recoverer, 25-ash residue pool, 26-limestone storage bin, 27-lime waste heat recoverer, 28-lime bin and 29-lime raw material inletThe device comprises a port, 30-an air seal chamber, 31-a kiln head cover, 32-a calcium carbide tail gas outlet, 33-an ash pool protective gas inlet, 34-a transport vehicle protective gas inlet, 35-a lime cooling gas inlet, 36-a flue gas inlet and 37-a flue gas outlet.

Detailed Description

The present invention will be described in detail with reference to the following examples and drawings. The scope of protection of the invention is not limited to the embodiments, and any modification made by those skilled in the art within the scope defined by the claims also falls within the scope of protection of the invention.

The lime-calcium carbide combined production system comprises a lime rotary kiln 2, a calcium carbide rotary kiln 17, a gasification heating furnace 1, a limestone storage bin 26, a calcium carbide raw material bin 19 and CO as shown in figure 1₂And a recovery device 16. The lime rotary kiln 2 is provided with a circulating gas inlet 9, a lime tail gas outlet 3, a limestone raw material inlet 29 and a lime product outlet 10, a limestone storage bin 26 is connected to the limestone raw material inlet 29, and the limestone storage bin 26 is provided with a flue gas inlet 36 and a flue gas outlet 37. The calcium carbide rotary kiln 17 is provided with a circulating gas inlet 9, a calcium carbide tail gas outlet 32, a calcium carbide raw material inlet 8 and a calcium carbide product outlet 18, and a calcium carbide raw material bin 19 is connected to the calcium carbide raw material inlet 8. The gasification heating furnace 1 is of a rotary kiln structure and comprises a fuel nozzle 6, a circulating gas outlet 4, an ash outlet 20 and an ejector 22, wherein the ash outlet of the gasification heating furnace is also allowed to be arranged on the circulating gas outlet side. The ejector 22 is provided with an ejection gas inlet 21, a tail gas ejection inlet 5 and an ejection opening, the ejection opening is connected to the gasification heating furnace 1, and a calcium carbide tail gas outlet 32 of the calcium carbide rotary kiln 17 is connected to the tail gas ejection inlet 5. The calcium carbide product outlet 18 is connected to the transport vehicle 7 through a calcium carbide waste heat recoverer 12, the lime product outlet 10 is connected to a lime bin 28 through a lime waste heat recoverer 27, the lime bin 28 is provided with a lime cooling gas inlet 35, and the ash residue outlet 20 is connected to a slag pool 25 through an ash residue waste heat recoverer 24. The transport vehicle 7 is provided with a transport vehicle shielding gas inlet 34, and the ash pond 25 is provided with an ash pond shielding gas inlet 33. The lime tail gas outlet 3 is connected to the flue gas inlet 36, the outlet of the flue gas outlet 37 is divided into two paths, one path is connected to CO₂And a recovery device 16, one path of which is connected to the inlet of the circulating pump 23. The outlet of the circulating pump 23 is divided into five paths, the first path is connected to the air seal chamber 30, and the second path is connectedAnd the third path is connected to a slag pool protective gas inlet 33, the fourth path is connected to a transport vehicle protective gas inlet 34, and the fifth path is connected to a lime cooling gas inlet 35 from the injection gas inlet 21. The circulating gas outlet 4 of the gasification heating furnace 1 is divided into two paths, one path is connected to the circulating gas inlet 9 of the calcium carbide rotary kiln 17 through a high-temperature hot carrier gas circulating pipeline 11, and the other path is connected to the circulating gas inlet 9 of the lime rotary kiln 2 through a high-temperature hot carrier gas conveying pipeline 15. As shown in fig. 2, the calcium carbide rotary kiln 17 is provided with a kiln head cover 31, an air seal chamber 30 is arranged between the kiln head cover and the kiln body, the kiln head cover is provided with a circulating gas inlet 9 and a calcium carbide product outlet 18, the circulating gas inlet 9 is positioned in the middle of the air seal chamber 30, the calcium carbide product outlet 18 is positioned at the lower part of the air seal chamber 30, and one path of the outlet of the circulating pump 23 is connected to the air seal chamber 30. The sealing structure of the lime rotary kiln and the gasification heating furnace is the same as that of the calcium carbide rotary kiln. As shown in fig. 3, the fuel nozzle 6 is of a coaxial sleeve structure, the center of the fuel nozzle is a pulverized coal passage 14, and the periphery of the pulverized coal passage is an oxygen passage 13. The gas seal chamber 30 may be a single or multiple seals, may be a static seal or a dynamic seal, may be a combination of mechanical and gas seals in a labyrinth, and may be sealed by a gas curtain using a gas including but not limited to carbon dioxide, nitrogen, inert gas or a mixture thereof to ensure that the gas in the rotary kiln does not enter the atmosphere, and the atmosphere does not enter the rotary kiln. In the embodiment, the sealing structures of the calcium carbide rotary kiln, the lime rotary kiln and the gasification heating furnace adopt a combination form of mechanical sealing and gas sealing of a labyrinth.

The discharge ports of all product materials and slag of the rotary kiln are sealed by carbon dioxide, so that the rotary kiln and the atmosphere are prevented from communicating. The carbide pot adopts a double-layer carbon dioxide protection device to prevent the carbide pot from being mixed with the atmosphere in the carbide rotary kiln. Any position of the calcium carbide rotary kiln and the gasification heating furnace allows an auxiliary heating device for plasma heating to be arranged.

The calcium carbide rotary kiln 17, the lime rotary kiln 2 and the gasification heating furnace 1 are allowed to have a structure only containing refractory materials, and kiln skins different from the refractory materials are hung on the refractory materials outside the inner ring. The calcium carbide rotary kiln and the gasification heating furnace system can also be used for other reduction smelting.

The invention relates to a lime-calcium carbide unitThe operation process of the combined production system comprises the following steps: the limestone raw materials in the limestone storage bin 26 are preheated by lime tail gas discharged from the lime rotary kiln 2 and then enter the lime rotary kiln 2 through a limestone raw material inlet 29, and coke and lime in the calcium carbide raw material bin 19 enter the calcium carbide rotary kiln 17 through a calcium carbide raw material inlet 8. The dried coal powder and pure oxygen are sprayed into the gasification heating furnace 1 through the fuel nozzle 6, and the coal powder, the pure oxygen and the calcium carbide tail gas are completely combusted in the gasification heating furnace 1 to generate CO basically₂Also allows for a certain proportion of CO, while also allowing for a certain amount of H including, but not limited to₂O、CH₄And H₂And becomes a high temperature thermal carrier gas. High-temperature hot carrier gas is discharged from a circulating gas outlet 4, one path of the high-temperature hot carrier gas enters a calcium carbide rotary kiln 17 through a high-temperature hot carrier gas circulating pipeline 11 and a circulating gas inlet 9 to heat calcium carbide raw materials to produce calcium carbide, the materials in the calcium carbide rotary kiln 17 are heated to 2000 ℃ to generate the calcium carbide and tail gas, the liquid calcium carbide is conveyed to a calcium carbide pot on a transport vehicle 7 through a calcium carbide product outlet 18, and the temperature of the liquid calcium carbide is 2000 ℃. The other path enters the lime rotary kiln 2 through a high-temperature hot carrier gas conveying pipeline 15 to heat and calcine limestone by using sensible heat to produce lime. The temperature of the high-temperature hot carrier gas at the circulating gas outlet 4 of the gasification heating furnace 1 is controlled to be 2300 ℃. Lime tail gas calcined in the lime rotary kiln is divided into two paths after the lime tail gas preheats the limestone raw material through the heat exchange coil 36, and the other path goes to CO₂The recovery device 16 purifies and recovers pure CO₂Removing water, purifying, and making into food grade or industrial grade CO₂The other path of the product is to the inlet of the circulation pump 23. CO at the outlet of the circulation pump 23₂Divided into five parts, the first part being sealed to the gas seal chamber 30, the CO in the gas seal chamber 30₂The air can be prevented from entering the rotary kiln, meanwhile, gas in the rotary kiln is prevented from leaking, the second part is used as working gas of the ejector from the guide gas inlet 21, the third part is used for providing protective atmosphere for the ash slag pool 25 from the ash slag pool protective gas inlet 33, the air is prevented from entering the gasification heating furnace, the fourth part is used for providing protective atmosphere for the transport vehicle 7 from the transport vehicle protective gas inlet 34, the air is prevented from entering the calcium carbide rotary kiln, the fifth part is used as cooling gas of finished lime from the lime cooling gas inlet 35, and the lime product is cooled by carbon dioxide. Calcium carbide tail gas of the calcium carbide rotary kiln 17 passes through the calcium carbide tailThe gas outlet 32 and the tail gas injection inlet 5 of the injector 22 enter the gasification heating furnace 1 as gas fuel, and the calcium carbide tail gas and pure oxygen in the gasification heating furnace are combusted to generate CO basically₂Also allows for a certain proportion of CO, while also allowing for a certain amount of H including, but not limited to₂O、CH₄And H₂And reasonable circulation air volume is ensured. The coal powder and coke can be replaced by other carbonaceous materials, and the method of gas circulation while gasifying can obviously reduce the consumption of the carbonaceous materials. The high-temperature ash discharged from the gasification heating furnace 1 enters an ash residue waste heat recoverer 24, and the ash residue after waste heat recovery enters an ash residue pool 25 and is recycled. The lime produced by the lime rotary kiln 2 enters a lime bin 28 after heat is recovered by a lime waste heat recoverer 27. Liquid calcium carbide produced by the calcium carbide rotary kiln 17 enters a calcium carbide waste heat recoverer 12 through a calcium carbide product outlet 18 to recover waste heat, then falls into a transport vehicle 7, and is transported out of the system by a trolley.

The main component of the calcium carbide tail gas discharged from the calcium carbide tail gas outlet 32 is CO₂、CO、H₂And H₂O, the gas discharged from the circulating gas outlet 4 of the gasification heating furnace 1 is substantially CO₂Also allows for a certain proportion of CO, while also allowing for a certain amount of H including, but not limited to₂O、CH₄And H₂And the temperature can be adjusted according to the design parameters of the rotary kiln. Depending on the process, CO removal can also be retained at the recycle gas outlet 4 of the gasification furnace 1₂And H₂If so, the gas removed from the lime rotary kiln 2 through the high-temperature hot carrier gas conveying pipeline needs to be afterburned by adding oxygen into the lime rotary kiln 2, and the gas can be afterburned or not after reaching the circulating gas inlet of the calcium carbide rotary kiln 17 and directly enters the calcium carbide rotary kiln 17.

As shown in fig. 2, the operation process of discharging and sealing the rotary kiln is described by taking the rotary calcium carbide kiln 17 as an example. When the calcium carbide rotary kiln 17 does rotary motion, a kiln head cover 31 of the rotary kiln is fixed. The liquid calcium carbide flowing out of the calcium carbide rotary kiln firstly flows into the kiln head cover and flows into the calcium carbide pot of the transport vehicle from the lower part of the kiln head cover. A certain gap is kept between the rotary kiln and the fixed kiln hood, so that a rotary kiln cylinder and the fixed kiln hood are bonded together by the solid calcium carbide which is not condensed when the rotary kiln is stopped, and the next start-up operation of the rotary kiln is not influenced. The structure of the air seal chamber adopts a combination form of mechanical seal and air seal of a labyrinth, the function of the air seal chamber is to prevent atmospheric air from entering the rotary kiln, and the consumption of seal gas can be reduced.

As shown in fig. 3, the fuel nozzle 6 is of a coaxial sleeve structure, the center of the fuel nozzle is a pulverized coal passage 14, and the periphery of the pulverized coal passage is an oxygen passage 13. Pulverized coal and oxygen conveyed by carbon dioxide enter the fuel nozzle 6, so that the pulverized coal and the oxygen can be sprayed into the gasification heating furnace from separate channels of the nozzle, and gas-solid material channels are coaxially distributed, thereby not only ensuring the safety of material conveying, but also ensuring that the materials are fully mixed by means of the spraying kinetic energy after being sprayed into the gasification heating furnace, and creating necessary conditions for the combustion of the pulverized coal and the oxygen. Carbide raw material powder is carried by carbon dioxide, spouts on carbide rotary kiln high temperature melting's material inner wall through 8 side directions of carbide raw material entry, makes raw material powder bond on high temperature melting material, reduces tail gas and carries raw material powder. The calcium carbide raw material can also be made into shapes including but not limited to balls and the like and enters the calcium carbide rotary kiln.

The lime-calcium carbide combined production system adopts tail gas circulation of a calcium carbide rotary kiln and pure oxygen combustion to generate CO basically₂The high-temperature gas, the coal burning quantity and the oxygen consumption are greatly reduced, and the produced calcium carbide has higher purity. Most of ash content of the coal after passing through the gasification heating furnace can be removed, and part of ash content in the calcium carbide raw material can also be removed by being carried by the calcium carbide rotary kiln gas, so that the purity of the calcium carbide can be improved. If a proper amount of iron powder is added into the calcium carbide melt, the silicon element and the iron element in the calcium carbide liquid ash are removed in the form of ferrosilicon, the ferrosilicon method can remove part of the slag amount of calcium carbide raw material coal and lime, and can also improve the purity of the calcium carbide.

The ejector can be replaced by other power devices which can achieve the purpose of ejection. The ejector and the fuel nozzle are close to each other as much as possible, so that the pulverized coal, the oxygen and the combustible gas are mixed and contacted sufficiently, and the reaction efficiency of the combustible gas is increased. The calcium carbide raw material is conveyed by carrier gas, including but not limited to, the calcium carbide raw material is conveyed by carbon dioxide and other stable gases and is laterally sprayed onto the inner wall of the high-temperature molten material of the calcium carbide rotary kiln through a nozzle, so that the raw material powder is bonded on the high-temperature molten material, and the raw material powder carried by tail gas is reduced.

Before entering a transport vehicle, the calcium carbide enters a calcium carbide waste heat recoverer 12, so that energy of waste heat recovery enters the system shown in the figure 1 and is used as energy for calcium carbide and lime production; lime produced by the lime rotary kiln enters a lime waste heat recoverer 27 before entering a lime bin 28, so that energy of waste heat recovery also enters the system shown in the figure 1 and is used as energy for calcium carbide and lime production. The calcium carbide tail gas outlet 32 of the calcium carbide rotary kiln 17 and the lime tail gas outlet 3 of the lime rotary kiln 2 are as close as possible to the gasification heating furnace 1, so that the safe operation of the system is facilitated.

The gasification heating furnace 1 has a higher pressure level than the lime rotary kiln 2 and the calcium carbide rotary kiln 17. The gasification heating furnace, the calcium carbide rotary kiln, the lime rotary kiln and the kiln head cover are all composed of refractory materials, heat-insulating materials and steel shells. All equipment and pipelines with temperature are provided with refractory material structures or water-cooled wall structures with internal heat preservation or external heat preservation or internal and external heat preservation.

When the calcium carbide rotary kiln is not in production and the ejector does not operate, high-temperature hot carrier gas discharged from a circulating gas outlet of the gasification heating furnace automatically enters the lime rotary kiln.